Multilayer PCB Via Structure for Deep Blind-Hole Electroplating
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Solution Overview
Problem
Existing methods for forming blind holes in printed circuit boards are limited by insufficient depth and aspect ratio, particularly in thick multilayer boards, leading to ineffective electroplating and hindered high-speed signal transmission.
Innovation Solution
A method involving mechanical drilling and laser processing to form through and blind holes, with a connection groove, allowing electrolyte solution flow to create a conductive layer for electrical connection between layers, and filling the groove with a medium to enhance electroplating and signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing methods are used to form blind holes in printed circuit boards, then the manufacturing process is simple, but the hole depth and aspect ratio are insufficient, leading to ineffective electroplating
Solution Approach 1:
The patent combines mechanical drilling and laser processing into a hybrid manufacturing system. The mechanical drill creates the initial hole structure, and the laser subsequently deepens and refines the hole to achieve the required depth and aspect ratio for effective electroplating in thick multilayer boards.
Solution Approach 2:
The connection groove acts as an intermediary structure that facilitates electrolyte solution flow between the through hole and blind hole. This groove enables the electroplating process to effectively reach deep blind holes by providing a dedicated fluid passage, thereby resolving the issue of insufficient electroplating in deep holes.
2Reliability
If through holes and blind holes are formed to enable high-speed signal transmission, then signal transmission performance improves, but the manufacturing complexity increases due to multiple drilling operations
Solution Approach 1:
The patent segments the signal transmission path into through holes for power/ground connections and blind holes for signal connections. This segmentation allows optimization of each hole type for its specific function, with through holes providing robust electrical connection and blind holes enabling high-speed signal transmission by avoiding via stubs.
Solution Approach 2:
The connection groove serves as an intermediary that connects the through hole and blind hole systems, allowing the electrolyte solution to flow between them during electroplating. This enables simultaneous or sequential plating of both hole types using a unified process approach.
3Adaptability or versatility
If the multilayer printed circuit board thickness increases, then more wiring layers can be accommodated, but existing blind hole formation methods become ineffective due to insufficient depth
Solution Approach 1:
The patent changes the key parameter of hole depth by combining mechanical drilling (for initial structure) with laser processing (for deepening). This parameter change enables the formation of sufficiently deep blind holes in thick multilayer boards, achieving aspect ratios adequate for effective electroplating regardless of board thickness.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables effective electroplating and high-speed signal transmission in multilayer printed circuit boards of varying thicknesses by ensuring adequate hole depth and aspect ratio, improving practicality and connectivity.
Implementation Method 1
drilling a reflow hole in the multilayer printed circuit board using a mechanical drill
Implementation Method 2
drilling from the bottom surface of the first hole position to the upper surface of the wiring layer using laser
Implementation Method 3
allowing an electrolyte solution to flow through the through hole, the connection groove, and the blind hole to form a conductive layer
Data Source
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AI summary
This application relates to the field of communication technology, and in particular, to a printed circuit board manufacturing method and a printed circuit board. The method includes: forming a through hole in a multilayer printed circuit board that runs through the multilayer circuit board, where the multilayer printed circuit board is provided with an upper printed circuit board, a wiring layer, and a lower printed circuit board that are stacked; forming a blind hole from the upper printed circuit board to the wiring layer in the multilayer circuit board; drilling between the through hole and the blind hole to form a connection groove, where the through hole is in communication with the blind hole through the connection groove; and allowing an electrolyte solution to flow through the through hole, the connection groove, and the blind hole to form a conductive layer, achieving an electrical connection between the upper printed circuit board and the lower printed circuit board.